Catalytic treatment of hydrocarbon oils



Patented Feb. 11, 1941 UNITED STATES CATALYTIC TREATMENT OF HYDRO-CARBON OILS Preston L. Veltman, Beacon, N. Y., assignor, by mesneassignments, to The Texas Company, New York, N. Y., a corporation ofDelaware No Drawing.

This invention relates to the catalytic treat- .ment of hydrocarbons andparticularly to the into low molecular weight hydrocarbons for theproduction of hydrocarbons suitable for the manufacture of internalcombustion motor fuel. In addition, it has application to the reformingof hydrocarbons, such as the reforming-of naphtha hydrocarbons toimprove their value as constituents' of motor fuel. In accordance withthe invention the treatment of the hydrocarbons is accomplished bycontacting them with a solid substantially non-volatile catalystcomprising hydrated aluminum fluoride.

In the catalytic cracking of oils to produce gasoline it has been thecommon practice to employ as catalysts such materials as fullers earth,kieselguhr, activated clays, artificial zeolites, and syntheticcompositions composed essentially 'of alumina and silica. It has alsobeen proposed to incorporate in such catalysts various'metallic oxides,such as the oxides of chromium, molybdenum, etc.

Ordinarily the oil to be cracked is heated and vaporized and the hotvapors are brought into contact with the solid catalyst under controlledconditions of temperature and pressure. The reaction products, includinggas, gasoline hydrocarbons and higher boiling hydrocarbons, areseparated in conventional ways. During the conversion coke-like materialis deposited on the catalyst, reducing its activity and ability tocatalyze the hydrocarbon conversion, and it becomes necessary .toreactivate the catalyst. This is acomplished by binning off the cokewith a stream of air or oxygen-containing gas. After thus reactivatingthe catalyst, it may be reused in cracking additional quantities of oil.

I have found that hydrated aluminum fluoride provides an effectivecracking catalyst and have discovered that catalysts containing thisfluoride may be prepared and employed in a form which gives resultssuperior to those obtainable with the solid catalysts previouslyemployed in the art.

In accordance with this invention the catalyst comprises hydratedaluminum fluoride or a compound or mixture containing aluminum fluoridein hydrated form. The catalyst may comprise hydrated aluminum fluoridealone or associated with other metallic fluorides and/0r solidmaterials, and disposed in asubstantially non-volatile form active attemperatures up to about 1100" F. and under pressures prevailing in thecatalytic cracking and reforming of petroleum hydrocarbons for theproduction of motor fuel.

Aluminum fluoride in the form of the hemisupport. Stated in another way,it may be de- Application December 30, 1939, Serial No. 311,943

7 Claims. (Cl. 196-52) hydrate, A1F3.%) H20, is stable at temperaturesup to 1200 F. It is known to exist as the monohydrate, AIF3.1H2O, attemperatures up .to about 500 F., and may exist, at leastpartly, in thishigher hydrate form at higher temperatures, particularly when associatedwith a solid carrier or other material as contemplated in thisinvention.

A preferred form of catalyst, which has been found particularlyeffective as a cracking catalyst, comprises solid hydrated aluminumfluoride associated with a solid adsorbent material, either natural orartificial. Such adsorbent materials include silicious materials, suchas fullers earth, clay, silica, silicates, aluminum silicates, zeolites,etc., as well as non-silicious materials, such as charcoal, alumina,magnesia, etc.

Other adsorbent materials may be used as supporting or carrier mediaupon which the fluoride may be adsorbed or dispersed. While adsorbentmaterials have been mentioned specifically, it is, nevertheless,contemplated that this secondary material may comprise otherfinely-divided or pulverulent solid materials.

The invention thus contemplates a composite or mixed catalyst consistingof hydrated aluminum fluoride, and particularly the hemi-hydrate, incombination with a secondary material or fined as a composite catalystconsisting of solid adsorbent material having the fluoride associatedwith the adsorbent material in a stable substantially non-volatile form.The catalyst is thought to be particularly effective when in aporousnonfused form.

The following are examples of specific catalysts which have been foundeffective:

1. Magnesium fluoride-silica-aluminum fiuoe ride catalyst in which themagnesium fluoride amounts to about 2% and the aluminum fluoride, in theform of the hemi-hydrate, amounts to about 6% by weight. This materialwas prepared by precipitating the magncsium fluoride in the presence ofsilica gel, finely-divided aluminum fluoride hydrate being added to themixture prior to precipitation of the magnesium fluoaround 1000 F. forfrom 6 to 8 hours were tested as cracking catalysts in the cracking of avirgin gas oil to produce gasoline. The tests demonstrated that theseparticular catalysts were effective in producing a high yield ofgasoline with low yields of gas and carbon,

Catalyst 1, for example, was compared with a standard catalyst, whichwill be subsequently referred to as Catalyst A, and which is asilicaalumina type of catalyst containing a high ratio of silica toalumina. According to this compari son, at a cracking temperature ofabout 1000 F.-, the fluoride catalyst gave a substantially higher yieldof gasoline than the standard catalyst. In addition, the yields of gasand carbon were substantially lower than were those obtained with thestandard catalyst.

The preparation of two catalysts, namely, Catalyst B, consisting of acompound containing about 80% SiOz, 15% MgFz, and AlF3- /zH2O, andCatalyst "0 comprising the above-mentioned standard Catalyst Acontaining about aluminum fluoride hemi-hydrate will now be describedmore specifically.

Catalyst B A batch of sodium-free hydrated silica was prepared byneutralizing a dilute solution of sodium silicate with dilutehydrochloric acid, filtering and washing free of sodium in the wetstate; 4,830 grams of this silica gel, containing approximately 400grams of SiOz, were slurrled with 10 liters of water until a uniformdispersion resulted. A finely ground mixture containing 30 grams ofammonium fluoride and 30 grams of AlFa- H2O, was added to the slurrywhile stirring, the stirring being continued for about 20 minutes. i

This slurry was then treated with about 2 liters of an aqueous solutionof magnesium chloride containing about 7% by weight of MgClz, andstirring continued for about one hour.

The pH was then adjusted to about seven with dilute hydrochloric andammonium hydrate solutions. The resulting precipitate was removed byfiltration and washed once by slurrying with water and filtering. Thewashed precipitate was dried to about 20% water content at 250 F. andpelleted. The pellets were calcined at about 1000" F. for six hours.

Catalyst "0 A batch of the previously mentioned standard Catalyst A, inthe form of pills, was moistened with aluminum chloride solution. Themoistened pills were heated at about 200 F. for about three hours so asto remove approximately one-half of the water added with the aluminumchloride solution. Thereafter the pills were cooled to room temperature.The cooled pills were then moistened with an aqueous solution ofammonium fluoride. These pills were then maintained at a temperature ofaround 212 F. until dry. Following this they were calcined by heating at1000 F. for four hours.

The aluminum chloride and ammonium fluoride solutions used were ofsufiicient concentration to produce a final product containing 10% byweight of aluminum fluoride.

Experiments were conducted for the purpose of comparing theeffectiveness of Catalysts "B and C with the standard Catalyst A in thecracking of virgin gas oil having an end boiling point of I00" F. andderived as a distillate from East Texas crude. The vaporized gas oil,heated to about 1000 F., was charged continuously to a tower, packedwith the catalyst in pill form,

at a space velocity of 2.2 (400 cubic centimeters of gas oil per hourper 180 cubic centimeters of catalyst). The tower was maintained at atemperature of 1000" F. and under atmospheric pressure.

The total liquid product obtained during successive intervals of timewas separately accumulated and analyzed to determine the content of idebutanized gasoline having an end boiling point of 400 F.

Comparison of yields (volume percent basis charge) obtained withCatalysts ".4 and B Catalyst 1 A 1! Catalyst 4 KB 1) Sample period,hours:

Gas and carbon yields percent basis charge average for first two hourson stream Catalyst A! 7 Catalyst Gas l8. l0. 9 Carbon 3. 0. 9

As the foregoing data reveal, Catalyst B, comprising the aluminumfluoride compound, did not lose its activity nearly so rapidly as didstandard Catalyst A. Moreover, the average yields obtained with thefluoride catalyst were substantially greater than those obtained withthe standard catalyst.

In addition, the fluoride catalyst produced substantially less gas thanthe standard catalyst,

i. e., around 10.9% by weight as compared with 18.5% by weight on thebasis of the gas oil charged. Likewise, the carbon yield is very muchlower, being 0.9% as compared with 3.19% by weight for the standardcatalyst.

The reduction in carbon yield is of particular advantage since itpermits easier and quicker regeneration of the catalyst with lessopportunity for deterioration of the catalyst during regeneration.

The following tabulation afiords a brief comparison of the effectivenessof Catalysts A" and C when used in the catalytic cracking of the sametype of gas oil charge under similar conditions of temperature and spacevelocity.

This tabulation illustrates the substantial improvement in gasolineyield realized when the standard catalyst is used in combination withhydrated aluminum fluoride. The gasoline yield is much greater and theyield oi. gas is much less.

pill or powdered form.

Also, it will be observed that over the two hour period the aluminumfluoride catalyst apparently did not decrease in activity, whereas thestandard catalyst did lose activity.

. While a cracking temperature of 1000 F. is mentioned in the foregoingexamples, it is contemplated that the temperatures may vary considerablyfrom this range, for.example, from about 700 to 1100 F. Also, the spacevelocity may vary from that mentioned above and may range from around 1to 10. The pressure used may vary as desired and may be aroundatmospherlc to 100 pounds, for example.

It is an object of the invention to use a. solid type of catalystcontaining the fluoride in an active form and in a form which is stableand substantially non-volatile at temperatures up to about 1200 F. Itmay be employed in pellet,

The catalysts described above show an unexpected advantage in ease ofreactivation. The carbonaceous deposit on the catalyst is easily removedby an oxygen containing gas without substantial temperature rise in arelatively short time as compared with previously known catalysts. Whilethis is in part due to the smaller deposition of carbon with thesecatalysts, it is also thought that the carbon is deposited in a somewhatdifierent form, such that it is more readily burned from the catalyst.

While vapor phase cracking has been described above, it is contemplatedthat the catalysts of this invention may be employed in liquid phasecracking. The characteristic of low carbon deposition with thesecatalysts, even at low temperatures, i. e., 700 to 750 F., and thereforein the presence of liquid hydrocarbons, indicates their suitability forcracking under substantial pressures.-

It is contemplated that the powdered form of the catalyst isparticularly applicable to a cracking system wherein the catalyst ispassed continuously through the reaction zone.

Obviously, many modifications and variations of the invention, ashereinbefore set forth, may be made without departing from the spiritand scope thereof, and therefore only such limitations should be imposedas are indicated in the appended claims.

I claim:

1. A solid catalyst adapted for the thermal conversion of hydrocarbonoil at elevated temperatures which. comprises a compound containingmagnesium fluoride, silica and aluminum fluoride hemi-hydrate and whichcompound is substantially non-volatile at temperatures below about 1200F.

2. A solid catalyst adapted for the thermal conversion of hydrocarbonoil at elevated temperatures which comprises a compound containingaround 80% SiOz, 15% MgFz and 5% AlFaJ/zHaO and which compound issubstantially non-volatile at temperatures below about 1200 F.

3. In catalytic conversion reactions selected from the group consistingof cracking and reforming hydrocarbon oil to produce high octanegasoline hydrocarbons, the method which comprises heating the oil to atemperature in the range around 700 to 1100" F. and subjecting the thusheated oil to momentary contact with a Solid catalyst substantiallynon-volatile at temperatures below about 1200' F. and comprising acompound containing magnesium fluoride, silica and aluminum fluoridehemi-hydrate such that there is substantial conversion of the oil intogasoline hydrocarbons of high octane value with relatively small carbonformation.

4. In catalytic conversion reactions selected comprising a compoundcontaining magnesium fluoride, silica and aluminum fluoride hemihydrate,maintaining the heated vapors in contact with the catalyst during arelatively short period of time such that there is substantialconversion of the oil to gasoline hydrocarbons of high octane value withrelatively small carbon formation.

5. The method according to claim 4 in which the heated hydrocarbonvapors are maintained in contact momentarily with the catalyst.

6. In catalytic conversion reactions selected from the group consistingof cracking and reforming hydrocarbon oil to produce high octanegasoline hydrocarbons, the method which comprises heating the vaporizedoil to a temperature in the range of around 700 F. and above, subjectingthe heated vapors to intimate contact with a synthetic, substantiallysodium-free solid catalyst comprising a compound containing magnesiumfluoride, silica and aluminum fluoride hemi-hydrate, and maintaining theheated vapors in contact with the catalyst for a relatively short periodof time such that there is substantial conversion of the oil to gasolinehydro carbons of high octane value with relatively small carbonformation.

7. In catalytic conversion reactions selected from the group consistingof cracking and reforming hydrocarbon oil to produce high octanegasoline hydrocarbons the method which comprises heating the oil to atemperature in the range around 700 F. to 1100 F., and subjecting thethus heated oil to momentary contact with a solid catalyst substantiallynon-volatile at temperatures below about 1200 F. and comprising acompound containing around S102 15% MgFz and 5% AlF3. H2O, such thatthere is substantial conversion of the carbons of high octane value withrelatively small carbon formation.

PRESTON L. VELTMAN.

REFERENCES CITED The following references are of record in the file ofthis patent:

Comprehensive Treatise, vol. 5, page 302-4924,

oil into gasoline hydro-

